Birum et al., U.S. Pat. No. 3,132,169 (1964) (incorporated herein by reference), disclose the preparation of certain ((neocarbyl-substituted) mixed bis(halogenated))phosphorates. These phosphorates are useful flame retardants.
However, these phosphorates are typically mixtures wherein the bis(halogenated) moieties, in relation to the phosphorus, are, for example, not only (bromoalkyl)(chloroalkyl) but also bis(bromoalkyl) and bis(chloroalkyl). See, e.g., Brault et al., J. Organometallic Chem., 66, 71-79 (1974). Perhaps the presence of such a mixture of phosphorates is a reason Albright et al., U.S. Pat. No. 4,083,825 (1978), disclose that (3-bromo-2,2-dimethylpropyl)(2-bromopropyl)(2-chloropropyl)phosphorate is not a substantially nonscorching flame retardant with a flexible polyurethane foam.
Thus, a problem in the art is the simple and efficient preparation of higher purity ((neocorbyl-substituted) mixed bis(halogenated))phosphorates. Another problem is the production of polyurethane foams which are more highly marketable, such as, for example, in slabstock flexible foams in which scorch, odor, flame retardant efficiency and processability are among production characteristics needing improvement.